Distribution of multimedia (also referred to herein as “media” and/or “program(s)”), such as movies and the like, from network services to a client device may be achieved through adaptive bitrate streaming of the media. Typically, the media may be encoded at different bitrates and resolutions into multiple bitrate streams that are stored in the network services. Conventional adaptive bitrate streaming of media includes determining streaming conditions, e.g., an available streaming bandwidth at the client device, and then streaming a selected one of the different bitrate streams from the network services to the client device based on the determined conditions.
From the perspective of the network service, streaming media includes transmitting the media in response to requests from the client device. From the perspective of the client device, streaming media includes continuously requesting and receiving the media from the network services, and storing the received media in a buffer for subsequent presentation or playback, essentially, in near real-time. The buffered media may be presented, i.e., played back, in audio-visual form, for example.
The human visual system perceives a perceptual or subjective quality of streamed, presented media, and is able to detect small changes in the perceptual quality. The perceptual quality generally increases and decreases as the encoded bitrate of the streamed program (i.e., “streaming bitrate”) increases and decreases. Therefore, more or less available streaming bandwidth may translate to more or less perceptual quality, respectively.
Given the ever pressing need to conserve bandwidth at the client device, conventional streaming techniques tend to select a streaming bitrate deemed to be sufficiently high to meet an acceptable level of perceptual quality, based on the streaming bandwidth conditions determined at the client device, as mentioned above. This bandwidth-centric determination and selection at the client device does not take into consideration changes or variations in the content contained in the media itself over time as the media is streamed and, therefore, often results in unnecessarily high, and therefore, bandwidth-wasteful, streaming bitrates.
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